This invention relates to pitless adapters and particularly to the removable portion of a well which is mounted between ground level and a well casing, arranged to provide at least one underground distribution line.
In some types of well, the well casing, normally of tubular form, extends vertically from the production zone or zones to near the surface. Lateral distribution from the well is provided by an underground line located a substantial distance below ground level and at least below the frost level for the particular area. In addition to protecting against freezing, such an underground installation also protects the installation against damage, flooding and vandalism. While most present day pitless adapter systems are employed with water wells, it is contemplated that the present invention may be employed with any kind of well and, in particular, with oil wells where theft of oil from above-ground lines has become a serious problem. A pitless adapter provides a connecting device between the well casing and the surface, provides seals for the line from the well to the lateral distribution line, and provides the sealed joint for the pump actuator or the pump motor electric lines. In instances of well and pump maintenance, the elements of the pitless adapter must be removed for the withdrawal of the pump or pump-motor assembly.
The well fluid, usually water, is pumped to the distribution point by a pump which may be a turbine-type pump or a submerged pump. In the former, a shaft, rotated by an above ground motor, extends through the pitless adapter, down the production pipe (also called a drop pipe) to a rotary pump. In the submerged type, a totally enclosed motor and close-coupled pump are submerged in the well fluid, and power lines from the surface provide operating power. In either case, the elements extending through the pitless adapter and the head of the casing must be sealed so that pumped liquid is forced out the lateral distribution line and the well will not be contaminated by surface water.
It is, therefore, among the objects and advantages of the invention, to provide a simplified pitless adapter using standard components for major parts of the adapter.
Another object of the invention is to provide a pitless adapter arranged for use for a turbine pump as well as a submerged pump-motor assembly.
Yet another object of the invention is to provide a pitless adapter which is adequately sealed, by stainless steel seals, and which components are easily removed therefrom, having a flange cap for uplift of the components and providing a working surface.
Still another object of the invention is to provide a pitless adapter for large size pipes and casing, usually above about four inches, using standard size steel pipe components.
A further object of the invention is to provide a drop pipe fitting for easy assembly in and out of a pitless adapter.
The foregoing objects and advantages have been obtained by providing an elongated pre-assembled outer barrel unit constructed and arranged for slideable insertion of a pre-assembled spool unit at the well site in a manner which establishes positive sealing of the well distribution line solely by proper location of the spool unit within the barrel unit. A relatively thin wall (e.g 3/8 inch) relatively short length (e.g. 3 to 12 inch) lowermost portion of the barrel unit made of one piece of standard size steel pipe is fixedly attached to an upper end portion of the well casing pipe which has a wall thickness of approximately the same thickness or less than the lowermost portion. A relatively thick wall (e.g. 1/2 to 1 inch) relatively short length (e.g. 6 to 24 inch) intermediate portion of the barrel unit, made of one piece of standard size steel pipe and fixedly connected to the lowermost portion, is adapted to receive, seal and support the spool unit and provide a lateral fluid discharge connection to a discharge line. A relatively thin wall (e.g. 3/8 inch) relatively long (e.g. 3 to 12 foot) uppermost portion of the barrel unit, made of one piece of standard size steel pipe and fixedly connected to the intermediate portion, has a relatively thick strong radially extending flange welded at the upper end which is adapted to support a cover plate and sealing gasket for use with a submersible pump or a turbine motor for a turbine driven pump. A pair of vertically axially spaced annular sealing rings made of stainless steel material are fixedly mounted in the intermediate portion. A beveled annular seat is provided on the upper end of the lowermost portion which is located within the intermediate portion in closely downwardly spaced relationship to the lowermost sealing ring. The inner surfaces of the ring members and the seat are machined, and/or ground to provide smooth concentric abutment surfaces. The spool unit comprises a relatively short continuous length central tubular member having a pair of axially spaced parallel annular plate members fixedly attached on the outer periphery thereof. The plate members have smooth concentric annular outer peripheral surfaces of a diameter slightly smaller than the diameter of the annular inner surfaces of the sealing ring members and a vertical axial spacing equal to the vertical axial spacing of the ring members which is slightly greater than the diameter of the lateral discharge pipe connector member. A beveled annular machined seat is provided on the lower edge of the lower plate for abutting supporting engagement with the beveled seat on the upper end of the lowermost portion of the barrel unit. A relatively large size O-ring is mounted in an annular O-ring groove in the outer peripheral surface of each of the plate members. The O-ring members have a normal outside diameter greater than the diameter of the inner surfaces of the ring members so as to be compressed thereagainst when the spool unit is seated on the barrel unit. The upper end of the central tubular member is closed and the lower end is fixedly connected to the pump pipe. the plate members define a fluid chamber connected only to the pump pipe through one or more openings in the central tubular member and to the discharge pipe connection in the side wall of the barrel unit. Passages for downhole electrical cables, air hoses, and the like are provided by tubular members or the like extending axially across the fluid chamber and through the annular plate members.